ChemDraw (Mac) freezes (stops responding) when trying to save an existing ChemDraw file (edit).
We have found this issue in some user machine and the workaround for this issue is to reset the launch services database.
To reset the launch services database, open Terminal by going to Applications - Utilities - Terminal in your mac machine and paste the command below:
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user ; killall Dock
This may take a while if you have lots of apps (20-30 minutes or more).